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Aims: Patients with ischaemic cardiomyopathy (ICM) referred for catheter ablation of ventricular tachycardia (VT) are at risk for end-stage heart failure (HF) due to adverse remodelling. Local unipolar voltages (UV) decrease with loss of viable myocardium. A UV parameter reflecting global viable myocardium may predict prognosis. We evaluate if a newly proposed parameter, area-weighted unipolar voltage (awUV), can predict HF-related outcomes [HFO; HF death/left ventricular (LV) assist device/heart transplant] in ICM., Methods and Results: From endocardial voltage maps of consecutive patients with ICM referred for VT ablation, awUV was calculated by weighted interpolation of local UV. Associations between clinical and mapping parameters and HFO were evaluated and validated in a second cohort. The derivation cohort consisted of 90 patients [age 68 ±8 years; LV ejection fraction (LVEF) 35% interquartile range (IQR) (24-40)] and validation cohort of 60 patients [age 67 ± 9, LVEF 39% IQR (29-45)]. In the derivation cohort, during a median follow-up of 45 months [IQR (34-83)], 36 (43%) patients died and 23 (26%) had HFO. Patients with HFO had lower awUV [4.51 IQR (3.69-5.31) vs. 7.03 IQR (6.08-9.2), P < 0.001]. A reduction in awUV [optimal awUV (5.58) cut-off determined by receiver operating characteristics analysis] was a strong predictor of HFO (3-year HFO survival 97% vs. 57%). The cut-off value was confirmed in the validation cohort (2-year HFO-free survival 96% vs. 60%)., Conclusion: The newly proposed parameter awUV, easily available from routine voltage mapping, may be useful at identifying ICM patients at high risk for HFO., Competing Interests: Conflict of interest: None declared., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Competing Interests: Conflicts of interest: The authors have provided declaration of interest information for all relationships that might be perceived as real or potential sources of conflicts of interest. The full disclosures can be viewed in the Supplementary material online for this article, available online at [URL].

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Objectives: This study sought to evaluate whether right ventricular (RV) tissue heterogeneity on computed tomography (CT): 1) is associated with conduction delay in arrhythmogenic right ventricular cardiomyopathy (ARVC); and 2) distinguishes patients with ARVC from those with exercise-induced arrhythmogenic remodeling (EIAR) and control individuals., Background: ARVC is characterized by fibrofatty replacement, related to conduction delay and ventricular tachycardias. Distinguishing ARVC from acquired, EIAR is challenging., Methods: Patients with ARVC or EIAR and combined endocardial-epicardial electroanatomic voltage mapping for VT ablation with CT integration were enrolled. Patients without structural heart disease served as control individuals. Tissue heterogeneity on CT (CT heterogeneity) was automatically quantified within the 2-mm subepicardium of the entire RV free wall at normal sites and low voltage sites harboring late potentials (LP+) in ARVC/EIAR., Results: Seventeen patients with ARVC (15 males; age: 50 ± 17 years), 9 patients with EIAR (7 males; age: 45 ± 14 years) and 17 control individuals (14 males; age: 50 ± 15 years) were enrolled. Of 5,215 ARVC mapping points, 560 (11%) showed LP+. CT heterogeneity was higher at sites with LP+ compared to normal sites (median: 31 HU/mm; IQR: 23 to 46 HU/mm vs. median: 16 HU/mm; IQR: 13 to 21 HU/mm; p < 0.001). The optimal CT heterogeneity cutoff for detection of LP+ was 25 HU/mm (area under the curve [AUC]: 0.80; sensitivity: 72%; specificity: 78%). Overall CT heterogeneity allowed highly accurate differentiation between patients with ARVC and control individuals (AUC: 0.97; sensitivity: 100%; specificity: 82%) and between ARVC and EIAR (AUC: 0.78; sensitivity: 65%; specificity: 89%)., Conclusions: In patients with ARVC, tissue heterogeneity on CT can be used to identify LP+ as a surrogate for ventricular tachycardia substrate. The overall tissue heterogeneity on CT allows the distinguishing of patients with ARVC from those with EIAR and control individuals., (Copyright © 2020 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: This study sought to investigate the value of electroanatomical voltage mapping (EAVM) to distinguish cardiac sarcoidosis (CS) from arrhythmogenic right ventricular cardiomyopathy (ARVC) in patients with ventricular tachycardia from the right ventricle (RV)., Background: CS can mimic ARVC. Because scar in ARVC is predominantly subepicardial, this study hypothesized that the relative sizes of endocardial low bipolar voltage (BV) to low unipolar voltage (UV) areas may distinguish CS from ARVC., Methods: Patients with CS affecting the RV (n = 14), patients with gene-positive ARVC (n = 13), and a reference group of patients without structural heart disease (n = 9) who underwent RV endocardial EAVM were included. RV region-specific BV and UV cutoffs were derived from control subjects. In CS and ARVC, segmental involvement was determined and low-voltage areas were measured, using <1.5 mV for BV and <3.9 mV, <4.4 mV, and <5.5 mV for UV. The ratio between low BV and low UV area was calculated generating 3 parameters: Ratio 3.9 , Ratio 4.4 and Ratio 5.5 , respectively., Results: In control subjects, BV and UV varied significantly among RV regions. The basal septum was involved in 71% of CS patients and in none of ARVC patients. Ratio 5.5 discriminated CS from ARVC the best. An algorithm including Ratio 5.5  ≥0.45 and basal septal involvement identified CS with 93% sensitivity and 85% specificity. This was validated in a separate population (CS [n = 6], ARVC [n = 10]) with 100% sensitivity and 100% specificity., Conclusions: EAVM provides detailed information about scar characteristics and scar distribution in the RV. An algorithm combining Ratio 5.5 (area BV <1.5 mV/area UV <5.5 mV) and bipolar basal septal involvement allows accurate diagnosis of (isolated) CS in patients presenting with monomorphic ventricular tachycardia from the RV., (Copyright © 2020 American College of Cardiology Foundation. All rights reserved.)

Objectives: This study sought to evaluate the relation between 12-lead ventricular tachycardia (VT) electrocardiography (ECG) and VT-related anatomical isthmuses (AIs) in repaired tetralogy of Fallot (rTOF)., Background: Slow-conducting AIs are the dominant VT substrate in rTOF. Whether an AI is considered critical relies on pace mapping (PM) guided by the VT ECG., Methods: VT ECGs, electroanatomical mapping data and PM results were analyzed in 25 rTOF patients (group 1) (age 57 ± 13 years). Selection of PM and ablation sites was guided by VT ECG. In 7 patients (group 2) (age 33 ± 14 years), PM was systematically performed within all AIs, irrespective of the VT ECG., Results: In group 1, all 35 induced VTs (median VT cycle length 270 [interquartile range: 240 to 310] ms) were AI related. All 11 right bundle branch block (RBBB) VTs were related to AI3 (right ventricular septum if positive concordant [7 of 7]), coronary cusp if V2 transition break [3 of 4]). Left bundle branch block (LBBB) VTs with transition 

Background: Progressive activation delay after premature stimulation has been associated with ventricular fibrillation in nonischemic cardiomyopathy (NICM)., Objectives: The objectives of this study were (1) to investigate prolongation of the paced QRS duration (QRSd) after premature stimulation as a marker of activation delay in NICM, (2) to assess its relation to induced ventricular arrhythmias, and (3) to analyze its underlying substrate by late gadolinium enhancement cardiac magnetic resonance imaging (LGE-CMR) and endomyocardial biopsy., Methods: Patients with NICM were prospectively enrolled in the Leiden Nonischemic Cardiomyopathy Study and underwent a comprehensive evaluation including LGE-CMR, electrophysiology study, and endomyocardial biopsy. Patients without structural heart disease served as controls for electrophysiology study., Results: Forty patients with NICM were included (mean age 57 ± 14 years; 33 men [83%]; left ventricular ejection fraction 30% ± 13%). After the 400-ms drive train and progressively premature stimulation, the maximum increase in QRSd was larger in patients with NICM than in controls (35 ± 18 ms vs. 23 ± 12 ms; P = .005) and the coupling interval window with QRSd prolongation was wider (47 ± 23 ms vs. 31 ± 14 ms; P = .005). The maximum paced QRSd exceeded the ventricular effective refractory period, allowing for pacing before the offset of the QRS complex in 20 of 39 patients with NICM vs. 1 of 20 controls (P < .001). In patients with NICM, QRSd prolongation was associated with the inducibility of polymorphic ventricular tachycardia (16 of 39 patients) and was related to long, thick strands of fibrosis in biopsies, but not to focal enhancement on LGE-CMR., Conclusion: QRSd is a simple parameter used to quantify activation delay after premature stimulation, and its prolongation is associated with the inducibility of polymorphic ventricular tachycardia and with the pattern of myocardial fibrosis in biopsies., (Copyright © 2016 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: High idiopathic premature ventricular contractions (PVC) burden has been associated with PVC-induced cardiomyopathy. Patients may be symptomatic before left ventricular (LV) dysfunction develops. N-terminal pro-B-type natriuretic peptide (NT-proBNP) and circumferential end-systolic wall stress (cESS) on echocardiography are markers for increased ventricular wall stress. This study aimed to evaluate the relation between presenting symptoms, PVC burden, and increased ventricular wall stress in patients with frequent PVCs and preserved LV function., Methods and Results: Eighty-three patients (41 men; 49±15 years) with idiopathic PVCs and normal LV function referred for PVC ablation were included. Type of symptoms (palpitations, fatigue, and [near-]syncope), PVC burden on 24-hour Holter, NT-proBNP levels, and cESS on echocardiography were assessed before and 3 months after ablation. Sustained successful ablation was defined as ≥80% PVC burden reduction during follow-up. Patients were symptomatic for 24 months (Q1-Q3, 16-60); 73% reported palpitations, 47% fatigue, and 30% (near-)syncope. Baseline PVC burden was 23±13%, median NT-proBNP 92 pg/mL (Q1-Q3 50-156), and cESS 143±35 kdyne/cm(2). Fatigue was associated with higher baseline NT-proBNP and cESS (P<0.001, P=0.011, respectively). After sustained successful ablation, achieved in 81%, NT-proBNP and cESS decreased significantly (P<0.001 and P=0.036, respectively). Fatigue was independently associated with a significantly larger reduction in NT-proBNP. In patients with nonsuccessful ablation, NT-proBNP and cESS remained unchanged., Conclusions: In patients with frequent PVCs and preserved LV function, fatigue was associated with higher baseline NT-proBNP and cESS, and with a significantly larger reduction in NT-proBNP after sustained successful ablation. These findings support a link between fatigue and PVC-induced increased ventricular wall stress, despite preserved LV function., (© 2015 American Heart Association, Inc.)

Background: A recent meta-analysis demonstrated a survival benefit in post-infarction patients whose ventricular tachycardia (VT) was rendered noninducible by catheter ablation. Furthermore, patients with noninducible VT had a lower VT recurrence rate than did patients whose VT remained inducible after ablation., Objectives: The purpose of this multicenter cohort study was to assess whether noninducibility after VT ablation is independently associated with improved survival., Methods: Data from 1,064 patients who underwent VT ablation for post-infarction VT at seven international centers were analyzed. The ablation procedure was considered successful if no VT was inducible at the end of the procedure and unsuccessful if VT remained inducible or if programmed stimulation was not performed at the end of the ablation., Results: Median follow-up time was 633 days. Noninducibility was independently associated with lower mortality (adjusted hazard ratio: 0.65; 95% confidence interval: 0.53 to 0.79; p<0.001). Atrial fibrillation, diabetes, and age were other independent predictors of higher mortality. Ablation of only the clinical VT in patients who also had inducible, nonclinical VTs was not associated with improved survival., Conclusions: Noninducibility after VT ablation in patients with post-infarction VT is independently associated with lower mortality during long-term follow-up., (Copyright © 2015 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)